Differences in case mix and outcomes between Swiss and Scottish total knee arthroplasty patients
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The clinical benefits of total knee arthroplasty (TKA) are well defined, but little attention has been paid to the cross-cultural variation. The objective of this study was to compare case mix and outcomes following TKA in Swiss and Scottish patients.
Data from local registries at a Swiss and a Scottish orthopaedic hospital were extracted to evaluate: (A) age, sex, body mass index (BMI), self-reported health status (EQ-5D), and joint awareness (Forgotten Joint Score-12 (FJS-12)) at pre-surgery, (B) improvement in EQ-5D and FJS-12 scores from pre-surgery to 1 year, and (C) patient satisfaction at 1 year.
Data from 2075 Swiss and 994 Scottish TKA patients were available from the local registries. Swiss and Scottish patients differed in age (69.3 vs 68.8 years, p = 0.046), sex ratio (62.9% vs 56.9% women, p = 0.002) and BMI (29.6 vs 30.9, p < 0.001). At pre-surgery, FJS-12 scores were comparable (Swiss 12.1 vs Scottish 10.9, n.s.), but EQ-5D scores were better in Swiss patients (0.52 vs 0.40, p < 0.001). Post-operative improvement was greater in Switzerland for the FJS-12 (+ 55.1 vs + 32.2, p < 0.001), but not for the EQ-5D (+ 0.31 vs + 0.29, n.s.). The satisfaction rate was similar in both groups (88.3% vs 89.6%, n.s.).
Subtle cross-cultural variation was evident in TKA case-mix factors between the two countries. Satisfaction and improvement in health status were similar, while improvement in joint-specific outcome was notably greater in Switzerland. Understanding cross-cultural variability of the outcome has important implications when interpreting study and registry data from other countries and when counselling a patient in daily practice.
Level of evidence
Retrospective cohort, Level III.
KeywordsTotal knee arthroplasty Comparative study Patient-reported outcome Forgotten Joint Score-12 EQ-5D Cross-cultural
Body mass index
EuroQol 5 dimensions
Forgotten Joint Score-12
Total knee arthroplasty
Western Ontario and McMaster Universities Osteoarthritis Index
We thank the patients, the data coordinators and those involved in data collection at the respective hospitals for assistance with this project. In particular, we thank Deborah MacDonald (University of Edinburgh) for assistance with the Scottish dataset.
The authors received no financial support for the research, authorship, and/or publication of this article.
Compliance with ethical standards
Conflict of interest
Two authors are copyright holders of the Forgotten Joint Score-12. Royalties are payable for commercial use of the questionnaire.
Approval for registry data analysis was obtained from the local ethics committee in Switzerland (EKSG 10/138) and Scotland (16/SS/0026).
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